Electronic clock having audible time indication

ABSTRACT

The present invention is an electronic time indicating signal clock of a hand indication type. It has a time indicating signal generating function marking time by one or more electronic tones and a correction function in which the number of tones made for a set time may be easily corrected.

BACKGROUND OF THE INVENTION

The present invention relates to a time signal clock which indicates the time by moving a pointer with a motor drive, using a quartz oscillator or the commercial power frequency as the standard frequency, while giving time signals by sound.

Heretofore, in analog type electronic clocks or watches in which a quartz oscillator or the commercial power frequency is used as the standard oscillation source, the standard frequency is divided into a pulse signal of 1 Hz by a dividing circuit, this signal drives a step motor, and by interlocking the motor shaft with the hands, the time is indicated on the graduated face of the clock or watch.

With conventional clocks of this type, it is possible to provide visual perception of time by analog indication of time by the angle of the pointer, but they can not be equipped with a time signal generating means such as will produce a striking sound like such means provided in mechanical clocks.

However, not only the visual but also the auditory sense is a very important means of perceiving time. For example, it is possible to readily perceive the time by a time indicating sound signal while engaged in work without glancing at the clock repeatedly. Further, the time as signaled by sound may be perceived by a person outside the angle from which the face of the clock is visible. The conventional electronic clocks with indicating hands are deficient in that they have no time signal indicating means as described above.

BRIEF SUMMARY OF THE INVENTION

The present invention is intended to solve the above-described inconvenience and an object of the present invention is to provide a time signal clock equipped with a time signal generating means, such as a sound, source, and which also indicates the time by moving a pointer means, such as hands, with a motor drive under the control of a quartz oscillator or the commercial power frequency providing a standard frequency.

A further object of the present invention is to provide a time signal clock having a time indicating function created by electronic sounds.

A still further object of the present invention is to provide a time signal clock having a correction function, by which easy corrections of the number of times the time indicating function sounds for a set time may be made.

Other and further objects, features and advantages of the invention will appear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of a time signal indication section of a time clock, according to the present invention;

FIGS. 2 and 3 are circuit diagrams of the time signal indication section of a time signal clock, according to the present invention;

FIG. 4 is a wave form diagram of the signals at various points during the set time in the time signal clock shown in FIGS. 2 and 3;

FIG. 5 is a wave form diagram of the signals during the correction time in a time signal clock;

FIGS. 6 and 7 are circuit diagrams of the essential parts of other embodiments of the time signal indication section of a time signal clock of the present invention;

FIGS. 8 and 9 are circuit diagrams of other embodiments of a pulse oscillation circuit according to the present invention;

FIG. 10 is a circuit diagram of a circuit of the time signal clock of the present invention in which an integrated circuit is employed;

FIG. 11 is a front view of a time signal clock embodying the present invention;

FIG. 12 is a sectional side elevation view of the essential parts illustrating the construction of a set time detecting device of the time signal clock of the present invention;

FIG. 13 is an exploded perspective view of the construction of FIG. 12;

FIG. 14 is a view showing the relations between a lever, the minute hand wheel and the second hand wheel used in a time signal clock of the present invention; and

FIG. 15 is a time chart for explaining the manner of driving a time signal reed switch employed in the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

First, the time signal indicating section of a time signal clock of this invention is shown schematically in FIG. 1. In FIG. 1, the signal level of an input terminal I_(n1) changes when a detection signal produced when a time detection means detects the set time (for example, 0 minute and 0 second) is added thereto. The wave form of the input signal added thereto is shaped by a one-shot circuit 1 and transmitted to a pulse oscillation circuit 7 through a pulse oscillation control circuit 6. The pulses produced from the pulse oscillation circuit are counted by a counter circuit 3. Thereafter, the number of pulses counted by the counter circuit 3 is compared with the number of pulses previously memorized in a memory circuit 4 by a comparison circuit 5. Upon finding the numbers of pulses in agreement, an indication signal from the comparison circuit 5 is transmitted to the pulse oscillation control circuit 6, while a one is added to the number memorized in the memory circuit 4, and the pulse production from the pulse oscillation circuit 7 is stopped. The pulses produced by the pulse oscillation circuit 7 are converted into audible frequencies by a modulation circuit 8, and after being current-amplified by an output circuit 9, are transmitted to a time announcing device 10 such as an audio speaker or the like.

Furthermore, when it is necessary to correct the number of time indicating audio signals generated from the time announcing device, a time correction switch (not shown in this Figure) is operated and the switch operation-related signal is added to an input terminal I_(n2). The input signal added thereto is transmitted to a one-shot circuit 11 for producing a pulse at the time of the start of the correction-switch operation and at the time of the end of the correction-switch operation. Both pulses are applied to gate circuits 2 and 12, to the pulse oscillation control circuit, and to the memory circuit 4 as a reset signal thereof. The pulse produced from the one-shot circuit 11 at the time of the start of the correction-switch operation serves to generate pulses from the pulse oscillation circuit 7, and with the gate circuit 2 closed and the gate circuit 12 opened, the number of the pulses from the pulse oscillation circuit 7 is counted by the memory circuit 4. The pulses from the pulse oscillation circuit 7 are further applied to the time announcing device 10 through the modulation circuit 8 and the output circuit 9, whereby the specified number of the time indicating audio signals are produced. When the desired number of the time indicating signals have been produced, the correction switch operation is ended, and thereby a pulse is again produced by the one-shot circuit 11 and applied to the pulse oscillation control circuit 6, to stop the pulse production. Then, after completing the correction, the one-shot circuit 11 causes the gate circuit 2 to be opened, and the gate circuit 12 to be closed, and thereupon a one is added to the number memorized in the memory circuit 4.

In the following, a further detailed explanation of the block diagram of FIG. 1 will be made with reference to a circuit diagram of FIG. 2. In FIG. 2, the switch S₁ is a detection switch for detecting the set time and producing the signal to be added to the terminal I_(n1). The detection switch S₁ is composed of, for example, a reed switch and a permanent magnet installed on gears interlocked with the minute hand and the second hand, which magnet is so arranged as to approach the reed switch only when both the minute and second hands come to the position of 12 o'clock on the face of the clock. When the magnet approaches the reed switch, the switch is closed input I_(n1) is brought to the V_(SS) level (based on positive logic, the level on the low potential side of the power source is set to the "0" level, while that on the high potential side V_(DD) is set to the "1" level). Detailed description of the set time detection device is put off for now; the time announcing circuit is described first of all. The switch S₁ and a capacitor C₁ are each connected to the V_(SS) side of the power supply at one end, and at the other end, to one end of a resistance R₁, the other end of which is connected to the V_(DD) side of the power supply, and also to the input terminal of an inverter circuit (hereinafter abbreviated as I), I₁. The output of I₁ enters a shift register (hereinafter abbreviated as SR) SR₁ as the input thereto. The output of SR₁ enters SR₂ as the input thereto. The clock signal T₁ to SR₁ and SR₂ is the output signal from a CR oscillation circuit composed of inverters I₂, I₃ and resistance R₃ and capacitor C₃, which is the output from the inverter I₂, the period of which is ##EQU1## The output terminal Q of SR₁ is connected to an input terminal of I₄. The one-shot circuit 1 is composed of SR₁, SR₂ and I₄, with a NOR circuit (hereinafter abbreviated as NO) NO₁ receiving as the input thereto the output of I₄ and the output of SR₂.

A switch S₂ is a push button switch which is closed at the time of correction operation, and is brought to the V_(SS) level. The switch S₂ and a capacitor C₂ are each connected to the V_(SS) side at one end, and at the other end, to one end of a resistance R₂, the other end of which is connected to the V_(DD) supply, and to the input terminal of I₅. The output terminal of I₅ is connected to the input terminal of SR₃, and the output terminal of SR₃ to an input terminal of SR₄. The aforementioned clock signal T₁ is supplied to the clock signal terminals of SR₃ and SR₄. The output terminal of SR₃ is connected to the input terminal of I₆. One-shot circuit 11 is composed of SR₃, SR₄, I₆ and NOR circuit NO₂ receiving, as the inputs thereto, the output of I₆ and the output of SR₄.

The output terminal of SR₄ is also connected to the input terminal of I₇, and another one-shot circuit is formed with a NOR circuit NO₃ receiving, as inputs, the output of I₇ and the output of SR₃. An OR circuit (hereinafter abbreviated as OR) OR₁ receives, as inputs, the outputs a, b from NO₁ and NO₂. The output of OR₁ enters, as a set input, a RS flip-flop (hereinafter flip-flop being abbreviated as F/F) composed of two NOR circuits NO₄ and NO₅. The output terminal of I₅ is further connected to the input terminal of I₈. The output from an AND circuit (hereinafter abbreviated as AN) AN₁ receiving, as inputs, the output of I₈ and an output of SR₁₃ enters OR circuit OR₂, together with the output C from NO₃, as an input thereto. The output e of OR₂ is added to the RSF/F, as the reset input.

In the pulse oscillation circuit 7, one end of a resistance R₄ and a capacitor C₄ is connected to the input terminal of inverter I₉. The output terminal of I₉ is connected to the input terminal of a transfer gate circuit (hereinafter abbreviated as TG) TG₁ composed of a pair of field effect transistors (hereinafter abbreviated as FET), one a p-channel FET (hereinafter abbreviated as Tp) Tp₁ and the other an n-channel FET (hereinafter abbreviated as Tn) Tn₁. The output terminal of TG₁ is connected both to the other end of the resistance R₄ and to an output terminal of another TG₂ composed of Tp₂ and Tn₂, the input terminal of which is connected to the V_(DD) supply. The outputs of TG₁ and TG₂ are added to an I₁₀ and the output terminal thereof is coupled to the other end of the capacitor C₄. On the other hand, the gates of Tn₁ and Tp₂ are associated with an output terminal of RSF/F, i.e., the output d of NO₄. The gates of Tp₁ and Tn₂ are associated with an output of RSF/F, i.e., the output d of NO₅. This output is in the inverse phase to the output d of NO₄, whereby the pulse oscillation circuit 7 is operated to produce pulses for the time indicating signals in synchronization with the set input.

The output of I₁₀, is converted into a pulse with a low duty cycle through a differential circuit composed of an inverter I₁₁, resistance R₅, capacitor C₅ and diode D and through a wave form shaping inverter I₁₂, thus producing pulse g which is supplied to the modulation circuit 8. The output of I₁₀, together with the output of I₈, enters AN₂ as an input, and the output terminal of AN₂ is coupled to the input terminal of the counter circuit 3, that is the input terminal of F/F₅. The counter circuit is so arranged that an output terminal of F/F₅ is connected to an input terminal of F/F₆, an output terminal of F/F₆ to an input terminal of F/F₇ and an output terminal of F/F₇ to an input terminal of F/F₈. The output terminal of a NAND circuit (hereinafter abbreviated as NA), NA₁ receiving, as inputs, an output from the pulse oscillation circuit 7, i.e., the output f of I₁₀ and the output of I₅, and an output terminal of NA₃ receiving, as inputs, both the output of I₈ and the output from the OR circuit OR₃ receiving, as the inputs, both the output C from NO₃ and the output from the comparison circuit 5, i.e., the output h of NO₅, are connected to the input terminal of NA₂. The memory circuit 4 has an input terminal φ of F/F₉ which is so arranged that an output terminal of F/F₉ connected to an input terminal of F/F₁₀, an output terminal of F/F₁₀ to an input terminal of F/F₁₁, and an output terminal of F/F₁₁ to an input terminal of F/F₁₂. An AND circuit AN₃ receiving, as its inputs, the outputs of F/F₁₀, F/F₁₁ and F/F₁₂ has an output terminal attached to an input terminal of SR₁₅. An output i from OR₄ receiving, as inputs, the output of SR₁₅ and the output b of NO₂ is transmitted to F/F₉ through F/F₁₂ as the reset input, whereby the memory circuit 4 is composed as a triodecimal counter. Both the output terminal of F/F₉ and the output terminal of F/F₅ are coupled to input terminals of an Exclusive OR (hereinafter abbreviated as EX) EX₁, then, the output terminals of F/F₁₀ and F/F₆ to input terminals of EX₂, the output terminals of F/F₁₁ and F/F₇ to the input of EX₃, and the output of F/F₁₂ and F/F₈ to the input of EX₄. The outputs from EX₁, EX₂, EX₃ and EX₄ are all transmitted to an NOR circuit NO₄ as inputs. The output terminal of NO₄ is connected to an input terminal of SR₁₃, and an output of SR₁₃ to an input terminal of SR₁₄. The output from SR₁₃ is transmitted to the AND circuit AN₁ as the input, as described previously, and is also supplied as the reset inputs to F/F₅ through F/F₈. The output from SR₁₃ is also supplied to the input terminal of the inverter circuit I₁₃. Then, the NOR circuit NO₅ constituting a one-shot circuit receives, as inputs, the output of I₁₃ and the output of SR₁₄, and the output, i.e., the output h of NO₅ is transmitted to the OR circuit OR₃ as the input, as previously described.

The modulation circuit 8 to which the output g from the inverter I₁₂ is added, the output circuit 9 and the time announcing device 10, are shown in FIG. 3. The output g from I₁₂ is transmitted to the gate of the n-channel FET Tn₃. The source of Tn₃ is coupled to V_(SS) and the drain thereof is connected to one end of the resistance R₆ connected to the V_(DD) supply at the other end and to one end of a capacitor C₆ coupled to V_(SS) at the other end, and is also associated with an input terminal of a transfer gate TG₄ composed of a pair of transistors Tp₄ and Tn₄. The output k of TG₄ is supplied to the base of a pnp transistor Tr₁. The clock signal T₁ is supplied to the gate of Tp₄, and the inverse phase signal T₁ through an inverter I₁₄ to the gate of Tn₄. The emitter of Tr₁ is coupled to the V_(DD) supply, and the collector thereof to the base of the npn transistor Tr₂. The emitter of Tr₂ is connected to V_(SS), and the speaker is coupled between the collector of Tr₂ and the V_(DD) supply. Actual examples of the resistances and capacitors used in FIGS. 2 and 3 are listed in the table below.

    ______________________________________                                         R.sub.1 = 100 KΩ                                                                          C.sub.1 = 0.05                                                                               μF                                           R.sub.2 = 100 KΩ                                                                          C.sub.2 = 0.05                                                                               μF                                           R.sub.3 =  47 KΩ                                                                          C.sub.3 = 0.022                                                                              μF                                           R.sub.4 = 820 KΩ                                                                          C.sub.4 = 1   μF                                           R.sub.5 =  33 KΩ                                                                          C.sub.5 = 10  μF                                           R.sub.6 =  1 KΩ                                                                           C.sub.6 = 4.7 μF                                           ______________________________________                                    

In the following, the time announcing operation according to this invention is described with reference to the time charts of FIGS. 4 and 5. FIG. 4 is a wave form diagram of the signals at various points respectively corresponding to each letter mark in FIGS. 2 and 3 at the time of normal operation, and FIG. 5 those at the time of correction. In FIGS. 4 and 5, φ₅ denotes the wave form at the φ terminal of F/F₅ ; φ₉ the wave form at the φ terminal of F/F₉ Q₅ ˜Q₁₃, the wave forms at the Q terminals of F/F₅ ˜F/F₁₃ ; and D₁₃ the wave form at the D terminal of SR₁₃.

Now, as the signal level changes from the "1" level to the "0" level at the set time, as shown by S₁ in FIG. 4, the output a from the NOR circuit NO₁ is at the "1" level for one cycle period of the clock signal T₁. Then, the RSF/F composed of NO₄ and NO₅ is brought to the set state by the signal transmitted through OR₁, and the output d changes from the "0" level to the "1" level. Then, TG₁ assumes an "ON" state, while TG₂ assumes an "OFF" state. As a result, the pulse oscillation is started, and as the output, i.e., the output f of I₁₀, a continuous pulse of about 1 Hz is produced. At this time, AN₂ is opened, but NA₁ is closed; for this reason, the number of pulses is counted only at the counter circuit 3, but not at the memory circuit 4.

If it is assumed that, as shown by Q₉, Q₁₀, Q₁₁ and Q₁₂ in FIG. 4, the state "3", that is the state in which Q₉ and Q₁₀ are at the "1" level, and Q₁₁ and Q₁₂ at the "0" level, is stored in the memory circuit 4, when the counter circuit 3 is brought to the state "3", that is the state in which Q₅ and Q₆ are at the "1" level, and Q₇ and Q₈ at the "0" level, all the Exclusive OR's are in the identical state, thereby giving the output of the "0" level. As a result, the input D₁₃ of SR₁₃ changes from the "0" level to the "1" level. Then, the output Q₁₃ of SR₁₃ becomes the "1" level after a delay of one cycle period. As a result, Q₁₃ resets the internal state of F/F₅ through F/F₈, thereby changing Q₅ through Q₈ to the "0" level, and at the same time, Q₁₃ serves as the reset input to the RSF/F, thereby changing the output d again to the "0" level. Then, TG₁ is made nonconductive, and TG₂ is made conductive, causing the oscillation to stop. As the input D₁₃ of SR₁₃ changes from the "0" level to the "1" level, the output h of the one-shot circuit which constitutes the comparison circuit is at the "1" level only for one cycle period of the clock signal T. This signal is passed through OR₃, NA₃ and NA₂, to supply the input signal to the memory circuit 4, thereby advancing the internal state thereof by one from "3" to "4". That is to say, the state of Q₉ and Q₁₀ being at the "1" level and Q₁₁ and Q₁₂ at the "0" level changes to the state of Q₁₁ being at the "1" level, and Q₉, Q₁₀ and Q₁₂ at the "0" level. The oscillation output f is converted through the differential circuit into a pulse with a low duty cycle, as shown by g. Only when g is at the "1" level, Tn₃ assumes the "ON" state, and the drain of Tn₃ becomes the "0" level. When Tn₃ is in the "OFF" state, it changes to the "1" level with the time constant set by the resistance R₆ and the capacitor C₆. This signal is modulated into an audible frequency, for example, the clock signal frequency T₁, and the modulated signal is transmitted to the pnp transistor Tr₁ and npn transistor Tr₂, to effect the current amplification. Then, the speaker 10 in FIG. 3, produces the electronic sound having a reverberation effect in correspondence with the relaxation signal. In this way, there is produced the time indicating signal sounds a number of times corresponding to the time indicating number of the clock or watch.

In the following, the time correction for the time announcement is described. The correction of the time announcing number is made by closing the switch S₂. This operation is described with reference to FIG. 5. As the switch S₂ is closed by outside operation, the signal changes from the "1" level to the "0" level. Then, the output b from the NOR circuit NO₂ is at the "1" level for one cycle period of the clock signal T₁, as shown in FIG. 5. This signal is passed through OR₁ to bring RSF/F into the set state, causing the pulse oscillation to start, and continuous pulses of about 1 Hz are produced as the output f of I₁₀. Simultaneously therewith, the output b of NO₂ is passed through OR₄, to reset the F/F₉ ˜F/F₁₂ of the memory circuit. At this time, since AN₂ has already been closed, but NA₁ and NA₂ are opened, the number of pulses is counted only at the memory circuit 4, but not at the counter circuit 3. Accordingly, only the number of pulses corresponding to the specified time, for example, "3" o'clock are produced as the output f of I₁₀, and this output is passed through the differential circuit, the modulation circuit and the output circuit in the same manner as in the case of normal set time, thereby producing the electronic sound from the speaker. Then, if after producing the electronic sound of the specified number of times, for example, "3", the switch S₂ is opened, and as a result, the signal level changes from the "0" level to the "1" level, then the output c from the NOR circuit NO₃ is at the "1" level only for one cycle period of the clock signal T₁, and this signal is passed through OR₂, to bring RSF/F into the reset state, causing the pulse oscillation to stop. Simultaneously therewith, the output c of NO₃ is passed through OR₃, NA₃ and NA₂, and counted by the memory circuit as the addition of "1" to the internal state therein. In this instance, the state of "3" o'clock is changed into "4" o'clock. That is, the state of Q₉ and Q₁₀ being at the "1" level and Q₁₁ and Q₁₂ at the "0" level changes to the state of Q₁₁ being at the "1" level, and Q₉, Q₁₀ and Q₁₂ at the "0" level. Whereupon, the clock resumes the normal operation. Then, as the next set time (for example, 4 o'clock) comes, the detection signal is automatically supplied through S₁, to produce the electronic sound four times.

If the output h of NO₅ is directly added to NA₃ as the input, omitting OR₃, as is apparent from the previous description, the function of adding "1" to the memory circuit is eliminated. In that state, as the switch S₂ is operated to produce the desired number of times, for example, "4" times, which corresponds to the number of times the electronic sound is to be produced, the electronic sound is produced four times at the next set time.

If the output Q₁₅ of the shift resistor SR₁₅ is added to OR₄ as an input and to OR₂ as an input, when the electronic sound is produced through the speaker 10 of FIG. 3 by closing the correction switch S₂, the number of pulses corresponding to the electronic sound are counted by the memory circuit; then, as the internal state of the memory circuit becomes 13, that is, as all the outputs Q₉, Q₁₁ and Q₁₂ become the "1" level, the output Q₁₅ of SR₁₅ changes to the "1" level, and this output is passed through OR₂, to reset the RS flip-flop, causing the pulse oscillation to stop. Simultaneously therewith, the internal state of the memory circuit is cleared, with all the outputs of F/F₉ through F/F₁₂ turned to the "0" level. Then, a pulse having the "1" level for the width of the clock signal T₁ is produced as the output h of NO₅. However, because the gate of NA₃ is not opened, the "1" level is not counted into the memory circuit. If the switch S₂ is opened thereafter, a pulse is produced as the output c of NO₃, and which is passed through OR₃, NA₃ and NA₂, to have a "1" counted into the memory circuit.

While the correction switch S₂ continues to be closed, the pulse is produced, and the electronic sound evolves, for the length of the time proportional to the switch closing time. With the circuit construction of this invention, the number of the electronic sounds does not exceed 13; no greater number of the electronic sounds evolves even if the switch S₂ is kept closed. Thereafter, as the normal operation is resumed by releasing the switch S₂, the electronic sound is produced only once when the next set time comes, corresponding to 1 o'clock. In that way, the correction can be made with great ease.

When assembling the circuit of FIG. 2 using integrated circuits, a set type flip-flop F/F₉ may be used, as in FIG. 7, in place of a reset type flip-flop F/F₉ used in the memory circuit of FIG. 2. In that way, the OR circuit OR₃ may be omitted without impairing the function of the circuit of FIG. 2. Furthermore, in making the circuit with integrated circuits, the shift-resistor SR₁₅ may be omitted so that the output of AN₃ is supplied directly to the input terminal of OR₄.

The pulse oscillation circuit 7 composed of the inverters I₉ and I₁₀, the transfer gates TG₁ and TG₂, the resistance R₄ and the capacitor C₄ may be, instead, composed of a NAND circuit NA₄, an inverter I₁₅, the resistance R₄ and the capacitor C₄, by transmitting the output of RSF/F, i.e., d being the output of NO₄ to the input terminal l of NA₄ as shown in FIG. 8 and the output of I₁₅ to the input terminal of I₁₁. Furthermore, as shown in FIG. 9, the pulse oscillation circuit 7 may be composed of an NOR circuit NO₆, inverters I₁₆ and I₁₇, resistance R₄ and capacitor C₄, by transmitting the signal of the inverse phase to the output of RSF/F, that is the output of NO₅, to the input terminal m and the output of I₁₇ to the input terminal of I₁₁.

In the following, the pulse oscillation control circuit 6 will be described in detail. Since normally, the output of NO₄ is at the "0" level, and the output of NO₅ is at the "1" level, TG₁ is nonconductive, TG₂ is conductive and accordingly, the input of I₁₀ is at the "1" level. As a result, the output of I₁₀ changes to the "0" level, and on the electrode K₁, that is, one of electrodes of capacitor C₄, a negative charge is stored. The input of I₉ from resistance R₄ is at the "1" level and the output of I₉, at the "0" level. On the other electrode K₂ of capacitor C₄, a positive charge is stored. If under this condition, the output of NO₄ turns to the "1" level, and the output of NO₅ to the "0" level, TG₁ becomes conductive, and TG₂, nonconductive. Thereupon, the input of I₁₀ changes from the "1" level to the "0" level, and the charging is made along the path of V_(DD) →the positive power supply circuit of I₁₀ →the output of I₁₀ →the electrode K₁ of the capacitor C₄, while discharging is made along the path of the electrode K₂ of the capacitor C₄ →the resistance R₄ →the input of I₁₀ →TG₁ →the output of I₉ →the negative power supply circuit of I₉ →V_(SS). As the above-described charging-discharging proceeds, the potential of the input of I₉ falls from the V_(DD) level to the V_(SS) level. Then, when the potential becomes less than the threshold voltage, the output changes from the "0" level to the "1" level, while the input of I₁₀ changes from the "0" level to the "1" level, and charging is made along the path of V_(DD) →the positive power supply circuit of I₉ →the output of I₉ →TG₁ →the resistance R₄ →the electrode K₂ of capacitor C₄, while discharging is made along the path of the electrode K₁ →the output of I₁₀ →the negative power supply circuit of I₁₀ →V_(SS), whereby the input potential of I₉ again rises from the V_(SS) level to the V_(DD) level. By repeating the above-described charging-discharging, oscillation is effected, with the time constant determined by the product of resistance R₄ and capacitor C₄. To be noted is the fact that the oscillation is started by the change of the output of I₁₀ from the "0" level to the "1" level undergone, simultaneously as the output of RSF/F, that is, the output of NO₄, changes from the "0" level to the "1" level; namely, pulse oscillation synchronized with the output of RSF/F (the output of the pulse oscillation control circuit 6) is achieved.

By this construction, the output of the detection circuit and the time indicating pulses are perfectly synchronized with each other, so that any possible gap between the set time and the timing for generating the time indicating signal may be closed.

Note also that in making the differential circuit connected to the output terminal of I₁₀, the capacitor C₅ may be eliminated by adopting the circuit construction as shown in FIG. 10, i.e., the construction in which the clock signal T₁ is transmitted to the reset terminal of F/F₁₆.

Since the circuits contained in FIGS. 2 and 3, except for the oscillation circuit, are each composed of the NAND circuits, the AND circuits or the transfer gate circuits, each may be composed of NOR circuits and inverter circuits whereby they may be formed as integrated circuits by use of I² L in place of C-MOS. This method will permit the output transistors Tr₁ and Tr₂ to be formed on a common chip.

Next, the construction of the time detecting means will be described. FIG. 11 is a front view of a time signal clock embodying the present invention. In FIG. 11, a body 21 is provided with a driving means, not shown in this Figure, under the control of a standard frequency, by which a second hand 22, a minute hand 23 (long hand) and an hour hand 24 (short hand) are driven. Reference numeral 25 designates the graduated plate and 10, an audio speaker. A mark S₂ denotes a switch for time indicating signal correction.

Now, the mechanism for actuating the switch S₁ when the minute hand and the second hand indicate the set time is described. A sectional view of the essential parts of the time detecting mechanism and the exploded perspective view thereof are respectively shown in FIGS. 12 and 13. In these Figures, a second hand wheel 33 is disposed between base plates 31 and 32; a second hand shaft 34 is attached to the seconds hand wheel 33, and the tip thereof is projected through the base plate 31. The second hand wheel 33 has a pinion part 33a, gear part 33b and cam part 33c. A transmission wheel 35 similarly disposed between the base plates 31 and 32 consists of a pinion 36 and a gear 37 which meshes with the seconds hand wheel 33, the pinion 36 and the gear 37 being stepped-clutch-coupled. The integral number of steps of this stepped-clutch is chosen so as to satisfy the following relationship:

    n=Z.sub.2 /Z.sub.1,

where

Z₁ : The number of teeth of the pinion part 33a of the seconds hand wheel.

Z₂ : The number of teeth of the transmission wheel gear.

In this embodiment, Z₁ and Z₂ are chosen to be Z₁ =8, and Z₂ =64, and accordingly, the number of steps n is 8. On the cam part 36a formed on the pinion 36, eight bumps 36b are formed at equal intervals along the circumference thereof; and the gear 37 provided with eight holes 37a which engage with these bumps is mounted on the cam part 36a, and is pressed down with a spring 38, thereby composing the stepped clutch. Reference numeral 39 denotes a stop ring for preventing the spring 38 from being drawn out. The cam part 36a is formed with two notched parts 36c. A minute hand wheel 40 having a gear part 40a, a cam part 40b and a pinion part 40c, are movably engaged with a holding cylinder 41 formed on the base plate 31, the gear part 40a meshing with the pinion 36. A hand turning wheel 42 has the shaft passed through the base plates 31 and 32. When it is pressed down from the position shown in FIG. 12, the gear part 42a is meshed with the gear part 40a of the minute hand wheel 40, so that the timing adjustment may be made by turning the hand turning wheel in that state. An L shape level 43 is rotatably installed on the base plates 31, 32, is provided with a projected part 43a which engages with the cam part 33c of the seconds hand wheel 33 and a projected part 43b which engages with the cam part 40b of the minute hand wheel 40, and on the bottom side, with a protruded part 43c which engages with the notched part 36c of the cam part 36a. The lever 43 is, as shown in FIG. 14, normally biased by being pulled in the direction indicated by the arrow. A magnet 45 is securely held on the end part of the bottom side of the lever 43. Facing this magnet 45, a reed switch 46 is disposed, so that it assumes the "ON" state, as it is brought close to the magnet 45, and assumes the "OFF" state, as it is set apart therefrom.

In the following, the way of actuating reed switch 46 is described. Since the cam part 33c of the second hand wheel 33 makes one rotation in one minute; the cam part 36a provided with two notched parts 36c makes one rotation in eight minutes; and the cam part 40b of the minute hand wheel 40, makes one rotation in one hour; if the cam part 33c, the notched part 36c of the cam part 36a and the cam part 40b are so set as to engage with the projected parts 43a, 43c and 43b of the lever 43, when both the minute hand and the seconds hand indicate the set time, the lever 43 will operate every hour, turning the reed switch to the "ON" state. Thus, the time length of the engagement between the projected parts 43a, 43c and 43b of the lever 43 and the cam part 33c, the notched part 36c of the cam part 36a and the cam part 40b are respectively chosen to be several seconds, that is the time required for making the reed switch 46 the "ON" state, about 1 minute and about 4 minutes. The positions of the cam parts 33c, 36a and 40b are set so that the projected part 43c comes to engage with the notched part 36c about 30 seconds before the projected part 43a engages with the cam part 33c, and the projected part 43b with the cam part 40b about 2 minutes before. The minute hand and the second hand are so set as to indicate the set hour, for example, 12 o'clock, when these cam parts are set in the above-described positions; then, the reed switch 46 always becomes "ON" state when the minute hand and the second hand come to the positions for 12 o'clock. These timing relations are displayed in the time chart of FIG. 15. In FIG. 15, the abscissa represents time. The timing adjustments of the hands are made by turning the minute hand wheel 40, pinion 36, the minute wheel (not shown in this Figure) and the hour hand wheel (not shown in this Figure) by way of operating the hand turning wheel 42. Then, the pinion 36 is turned as the minute hand wheel 40 rotates, but because the pinion 36 and the gear 37 are stepped-clutch-coupled at 1/8 round pitch, a slip occurs between the pinion 36 and the gear 37. As a consequence, while the pinion 36 turns at 1/8 round pitch, the gear 37 does not turn. The second hand wheel 33, then, continues the turning for the hand movement irrespective of the timing adjusting operation of the hand turning wheel 42. Since the number of teeth of the pinion 36 is chosen to be 8, and the number of teeth of the gear part 40a of the minute hand wheel 40 is chosen to be 60, the pinion 36 results in (1/8)×(8/60)=1/60 round turning (1 minute) of the minute hand wheel 40. Thus, the pinion 36 is turned 1/8 round by the operation of the hand turning wheel 42, while the minute hand wheel 40 is turned thereby at 1 minute pitch, and the second hand wheel 33 continues its initial turning. Accordingly no mismatched positional relationship between the second hand and the minute hand will result from the timing adjusting operation for the hands.

If any error is recognized in the operation timing of the reed switch 46, the cam part 33c of the seconds hand wheel 33 may be removed. To do so, it is proper to set the minute hand and the second hand in place so as to indicate the set time when the projected part 43c and the notched part 36c of the cam part 36a are in their engaged position. It is also possible to provide projections instead of the notches on the cam.

With this arrangement, in which the second hand wheel, the transmission wheel and the minute hand wheel are respectively provided with cams, and the lever is provided with projections respectively to be engaged with the notches of the cams, the lever is operated when the engagements between each cam and each projection of the lever coincide, whereby the switch S₁ is actuated when not only the minute hand but also the second hand come to their respective set time position. In this way, a time indicating signal clock free of error in time indication is obtained.

Whereas in the foregoing embodiment, a system in which principally sound is employed as the time announcing means is described. Use of light as the time announcing means will be made possible by adding an output transistor to the output terminal of the oscillation circuit of FIG. 2, i.e., the output f of I₁₀, and connecting the output terminal of the output transistor to a light emitting transistor or a phototransistor.

As described in the foregoing, with the conventional electric or electronic clocks operated from a standard frequency source, only visual means are available for indicating the time, but this invention offers the possibility for indicating the time both visually and acoustically.

With this clock or watch, exact time can be indicated even in dark places or at night, etc. The whole set-up of the circuits, except for several resistances and capacitors, are amenable to integration, permitting low priced and very small time announcing devices to be made available. Since the pulses for the time indicating signals normally are not produced, lowered power consumption is inherently achieved. Because the switching of the switch S₁ occurs exactly at the set time, the electronic sound is produced in interlocked timing with the second hand, thus giving a very exact time announcement. Because the preparation for giving the next time announcement is made upon completion of a time announcement, this system involves little possibility of misoperations. At the time of correction, the number of pulses produced is directly counted in the memory circuit, permitting the correction of the time announcement to be made very easily by the mere operation of the correction switch. Moreover, the electronic sound produced from the speaker is a highly audible sound with reverberation effect due to the existance of the sustain circuit incorporated in the system. 

What we claim is:
 1. An electronic time indicating signal clock comprising:a time indicating means for indicating the time; a time measuring means connected to said time indicating means for causing said time indicating means to indicate the time; a detecting means associated with said time indicating means for detecting when said time indicating means indicates a particular periodic time for which it is desired to generate an audio time indicating signal; a pulse oscillation means for generating pulses; a pulse oscillator control means connected to said detecting means and said pulse oscillator means for causing said pulse oscillator means to repetitively generate pulses whenever said detecting means detects one of said particular periodic times until said pulse oscillator control means is reset; a time indicating signal generating means connected to said pulse oscillator means for generating a time indicating signal whenever said pulse oscillator means generates a pulse; a counting means connected to said pulse oscillator means for counting the number of pulses generated by said pulse oscillator means; a memory means for storing the number of time indicating signals desired to be produced; a comparison means connected to said counting means, said memory means and said pulse oscillator control means, for comparing the count of said counting means with the number stored in said memory means, for resetting said pulse oscillator control means when the count of said counting means equals the number stored in said memory means and for storing in said memory means the number of time indicating signals desired to be produced at the next occurring particular time period; and a correction means connected to said memory means and said pulse oscillator control means, including a correction switch for activating said pulse oscillator control means to cause said pulse oscillator means to generate pulses, for correcting the number stored in said memory means by storing a number in said memory means related to the number of pulses generated by said pulse oscillator circuit during the activation of said correction switch.
 2. An electronic time indicating signal clock as claimed in claim 1, wherein:said comparison means includes means to reset said counting means and means to add one to the number stored in said memory means when said comparison means resets said pulse oscillator control means.
 3. An electronic time indicating signal clock as claimed in claim 1, wherein:said correction means includes means for erasing the number stored in said memory means upon actuation of said correction control switch.
 4. An electronic time indicating signal clock as claimed in claim 1, wherein:said correction means includes means for causing said memory means to count the number of pulses generated by said pulse oscillator means under control of said correction control switch and for adding one to the number stored in said memory means when said correction control switch is deactivated.
 5. An electronic time indicating signal clock as claimed in claim 1, wherein:said time indicating signal generating means comprises an audio speaker and a reverberation effect producing means connected to said audio speaker, for generating a reverberation effect electronic sound.
 6. An electronic time indicating signal clock as claimed in claim 1, wherein:said detecting means comprises a permanent magnet which moves in response to said time measuring means and a stationary magnetically sensitive switch.
 7. An electronic time indicating signal clock as claimed in claim 1, wherein:said detecting means comprises a magnetically sensitive switch which moves in response to said time measuring means and a stationary permanent magnet. 